In order to meet increasingly stringent fuel economy and emission requirements, some modern internal combustion engines employ fuel systems where fuel under high pressure, typically higher than 10 MPa, is injected directly into combustion chambers by fuel injectors In a typical system, several fuel injectors are connected to a single fuel rail assembly. The fuel rail assembly includes an inlet for receiving pressurized fuel from a fuel source and a plurality of outlets connected to respective fuel injectors. The fuel injectors are sequentially actuated to deliver fuel from the fuel rail to the combustion chambers in sequence with the operation of the engine.
FIGS. 8-11 of United States Patent Application Publication No. US 2011/0108005 A1 to Nishizawa et al. show a typical fuel rail assembly. The fuel rail assembly includes outlets which are aligned with the axis of the fuel rail while mounting brackets are fixed to the fuel rail by brazing such that the mounting brackets are offset from the outlets. When pressurized fuel is supplied to the fuel injectors, the pressurized fuel generates a force, cyclic in nature due to opening and closing of the fuel injectors and cycling of a high pressure pump, which attempts to push the fuel injectors away from the internal combustion engine in a direction that is in-line with each fuel injector respectively. This force must be resisted by the mounting brackets. In addition to the forces generated by the fuel injectors and the high pressure pump, vibrations from the operation of the internal combustion engine and dynamics of a motor vehicle traveling on a roadway may induce fatigue loading on the fuel rail assembly which must be resisted by the mounting brackets. However, since the mounting brackets are rigid and are rigidly fixed to the fuel rail, the braze joint is subject to cyclic stress which in time may result in fatigue failure.
What is needed is a fuel rail assembly which minimizes or eliminates one or more of the shortcomings as set forth above.